status-go/vendor/github.com/anacrolix/torrent/bencode/scanner.go

39 lines
748 B
Go

package bencode
import (
"errors"
"io"
)
// Implements io.ByteScanner over io.Reader, for use in Decoder, to ensure
// that as little as the undecoded input Reader is consumed as possible.
type scanner struct {
r io.Reader
b [1]byte // Buffer for ReadByte
unread bool // True if b has been unread, and so should be returned next
}
func (me *scanner) Read(b []byte) (int, error) {
return me.r.Read(b)
}
func (me *scanner) ReadByte() (byte, error) {
if me.unread {
me.unread = false
return me.b[0], nil
}
n, err := me.r.Read(me.b[:])
if n == 1 {
err = nil
}
return me.b[0], err
}
func (me *scanner) UnreadByte() error {
if me.unread {
return errors.New("byte already unread")
}
me.unread = true
return nil
}